Timing mechanism



Aug. 2, 1966 v. D. LOKEN TIMING MECHANISM Filed Sept. 14, 1964 INVEN TOR. VERN D. LO'KEN ATTORNEYS:

United States Patent 3,263,611 TIMING MECHANISM Vern D. Loken, Minneapolis, Minn, assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Army Filed Sept. 14, 1964, Ser. No. 396,441 7 Claims. (Cl. 102-82) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a timing mechanism, and more particularly to a time delay mechanism adapted for use in munitions or the like.

In munitions and other fields, certain structures lend themselves to the use of circuits having a delay element employed to actuate switches, solenoids, relays and the like. The present invention is directed to a time delay arrangement of such nature and has even further use in rocket, mine and grenade fuzing systems. More specifically, it relates to a time delay mechanism which is fluid damped and operates on the dash pot principle.

One of the objects of the invention is to provide a time delay mechanism capable of retaining essential fluid damping media in a protective manner during long periods of storage.

Another object of the invention is to provide a time delay mechanism having means for closing an electric circuit as controlled by the damping fluid.

A further object of the invention is to provide a time delay mechanism having an actuating shaft and a separate electric circuit with contacts for indicating correct positioning of the shaft prior to actuation thereof.

Another object of the invention is to provide such a mechanism having a minimum number of parts.

These and other objects, advantages and features will become apparent from the following description and accompanying drawing which is a sectional view of the time delay mechanism embodying the principles of the invention.

In the preferred form of the invention the housing 11 is provided with a longitudinal passage 12 defining a chamber which suitably accommodates a slidable actuating shaft 13 having a forward pointed end 14 extending toward and aligned with the central portion of a tapered recess 16 in the rear surface of piston 17. Piston 17 is mounted in the rearmost portion of cylinder 18 which is closed at its forward end 19 and contains a predetermined amount of damping fluid 20. Extending across the rear of cylinder 18 and rearwardly adjacent piston 17 is a thin plastic membrane or closure member 21 which normally functions to sea-l ofl chamber 18 with the piston and damping fluid contained therein.

A transverse slot or passage 24 is provided in housing 11 in which a retaining ball 25 is preferably held by an appropriate removably mounted closure member 26. Ball 25 is of suflicient dimensions to have a portion thereof extend into the path of a laterally extending flange 28 of shaft 13.

An appropriately apertured capacitor contact member 29 receives the rearmost reduced shaft portion or plug 30 with predetermined clearance that when the latter engages battery contact 31, an electrical circuit is closed charging a capacitor (not shown). Conventional indicating means such as -a light bulb (not shown) may be employed in the circuit to render a signal that the shaft is in its rearmost or fully cocked position, whereupon energy is stored in compressed spring 32 that extends between flange 28 and contact 29. Contact 33 extends into the housing passage 12, terminating in the path of shaft flange 28 such that when shaft 13 is fully extended, in a manner to be described, another electrical circuit is energized through contact 33, shaft flange 28, spring 32 in its extended position and contact 29. This last mentioned circuit when closed causes the capacitor to fire an electric detonator (not shown) or any other device with which the mechanism is to be associated. Insulating strip 34 is disposed between opposed faces of contacts 29 and 31 to preclude premature closing of the first mentioned circuit.

In operation, when the closure member 26 is removed the spring biased shaft 13 plunges forward, pushing retaining ball 25 outward, and the pointed end 14 punctures the seal or membrane 21 before striking the recess of piston 17 to move the piston toward the chamber forward or closed end 19. As plug 30 moves forwardly away from spring contact 31, the latter is released to engage contact 29 to maintain the capacitor energized, thereon constituting a holding circuit. The speed of piston travel is retarded as its rate of displacing fluid 20 is dependent upon the rate of fluid flow past the piston periphery and through the ruptured membrane 21 surrounding the pointed end 14 of shaft 13. When the predetermined delayed forward motion of shaft 13 has proceeded until shaft flange 28 abuts contact member 33, the desired actuating or electrical circuit through contacts 33 and 29 is then established.

It is understood that various modifications, changes or alterations may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. A time delay mechanism for use with munitions and the like comprising,

a fluid damping chamber closed at one and and having therein fluid and a slidable piston which is controlled by said fluid,

means sealing the other end of said chamber adjacent said piston,

a housing having a passage communicating with said sealing means,

a shaft in said passage and having means extending toward said sealing means for puncturing same,

means biasing said shaft toward said piston,

means releasably restraining movement of said shaft from a cocked position, and

means on said shaft for closing an electric circuit upon predetermined movement of said shaft,

so constructed and arranged that upon release of said restraining means said shaft will puncture said sealing means, move said piston toward said chamber one end and close said circuit, the movement of said piston being retarded by said fluid.

2. A time delay mechanism for use with munitions or the like comprising,

a chamber closed at one end and containing a damping fluid,

a piston in said chamber positioned at the other end thereof,

means extending across and normally sealing said chamber other end adjacent one end of said piston,

a shaft aligned with said piston and having a pointed end extending toward said piston for puncturing said sealing means and displacing chamber fluid with said piston,

a housing having a longitudinal passage in which said shaft is movable,

means biasing said shaft toward said piston,

retractable means normally extending into said passage end maintaining said shaft in -a cocked position, and

means on said shaft for closing an electric circuit when said shaft reaches a predetermined extent of travel,

so constructed and arranged that upon retraction of said normally extending means, said shaft will be actuated by said biasing means to puncture said seal means and drive said piston toward said chamber one end.

3. The mechanism in accordance with claim 2 wherein said housing contains a separate electric circuit having contacts engagingseparate portions of said shaft in the cocked position thereof.

4. The mechanism defined in claim 2 wherein said piston has a recess therein for receiving said shaft pointed end.

5. The mechanism recited in claim 2 wherein one of said contacts is common to both of said circuits.

6. The mechanism of claim 5 in which said biasing means includes a spring interposed between said one contact and said circuit closing means.

7. The arrangement of claim 6 wherein said normally extending means includes a releasable ball seated in a housing transverse slot and having a portion thereof extending and normally held in the path of said circuit closing means.

No references cited.

BENJAMIN A. BORCHELT, Primary Examiner.

G. H. GLANZMAN, Assistant Examiner. 

1. A TIME DELAY MECHANISM FOR USE WITH MUNITIONS AND THE LIKE COMPRISING, A FLUID DAMPING CHAMBER CLOSED AT ONE END AND HAVING THEREIN FLUID AND A SLIDABLE PISTON WHICH IS CONTROLLED BY SAID FLUID, MEANS SEALING THE OTHER END OF SAID CHAMBER ADJACENT SAID PISTON, A HOUSING HAVING A PASSAGE COMMUNICATING WITH SAID SEALING MEANS, A SHAFT IN SAID PASSAGE AND HAVING MEANS EXTENDING TOWARD SAID SEALING MEANS FOR PUNCTURING SAME, MEANS BIASING SAID SHAFT TOWARD SAID PISTON, MEANS RELEASABLY RESTRAINING MOVEMENT OF SAID SHAFT FROM A COCKED POSITION, AND MEANS ON SAID SHAFT FOR CLOSING AN ELECTRIC CURCUIT UPON PREDETERMINED MOVEMENT OF SAID SHAFT, SO CONSTRUCTED AND ARRANGED THAT UPON RELEASE OF SAID RESTRAINING MEANS SHAFT WILL PUNCTURE SAID SEALING MEANS, MOVE SAID PISTON TOWARD SAID CHAMBER ONE END AND CLOSE SAID CIRCUIT, THE MOVEMENT OF SAID PISTON BEING RETARDED BY SAID FLUID. 